Some celebrities simply cannot be pleased. Just ask Ben Lashes, a talent manager in Los Angeles. This week, he landed a major motion-picture deal for a client who nine months ago was an unknown living in Morristown, Ariz., population 227.

When he told his client that she was heading to Hollywood, she looked bored. "She hates movies," says Mr. Lashes of his client, Grumpy Cat, a cat with a mouth puckered into a frown whose viral photos have ricocheted around the Internet.

Mr. Lashes, 34 years old, is an agent for Internet cats. When an ironic photograph of a feline becomes Internet famous, Mr. Lashes contacts the pet owner and offers to help strategize ways to prolong, protect and monetize. He says he operates with this question in mind: "What would Walt Disney do if he created Mickey Mouse and it went viral on YouTube?"

Grumpy Cat, the Arizona sourpuss, is Mr. Lashes's star client. The cat is having a mini-Mickey moment.

Last September, Bryan Bundesen, 34, a cable technician from Galion, Ohio, was visiting his sister Tabatha in Arizona. He snapped a photo of her cat, a mixed breed whose real name is Tardar Sauce. (Ms. Bundesen, who works as a waitress at a Red Lobster, says her daughter thought the cat's fur was the color of tartar sauce, but misspelled it.) Mr. Bundesen posted the picture on the website Reddit. People thought it was funny. Many began to overlay the photo with sentences expressing what they imagined to be the cat's irritation with humans: "I thought I could not be more disappointed…you proved me wrong," reads one of thousands. "There are two kinds of people in this world…and I don't like them," says another.

Within weeks, photos and videos of the cat had been shared and posted to social-media sites millions of times.

Mr. Lashes, whose legal name is Benjamin Clark, became the cat's representative in October. He says he is trying to help the Bundesens capitalize on the cat's fame without overexposing it. This week, Mr. Lashes helped negotiate the sale of a film option based on Grumpy Cat's persona to Broken Road Productions, the production company responsible for Adam Sandler's 2011 vehicle "Jack and Jill." Terms of the one-picture deal weren't disclosed.

This week, Grumpy Cat is coming to New York to promote the forthcoming Chronicle Books release, "Grumpy Cat: A Grumpy Book: Disgruntled Tips and Activities Designed to Put a Frown on Your Face" at BookExpo America, the publishing industry convention.

Mr. Lashes also has forged a deal with Grenade Beverage LLC to create and distribute a line of Grumpy Cat coffee-in-cans and bottled beverages. Excluding the movie deal, the Bundesens have earned a low-six-figure sum off the cat thus far, Mr. Bundesen says. Mr. Lashes's take is about 20%, clients say. (Mr. Lashes declined to comment on financial arrangements.)

"He is really good at helping us not get taken advantage of," Mr. Bundesen says of Mr. Lashes.

Mr. Lashes grew up in Spokane, Wash. After a year of college, he dropped out in 2000 to pursue his dream of becoming a professional musician. He fronted a band and worked in talent scouting for an independent label.

In 2010, he heard from Charlie Schmidt, an old friend of his father's and a multimedia artist in Spokane. Back in 1985, Mr. Schmidt told Mr. Lashes, he had dressed his now deceased cat, Fatso, in a blue T-shirt, sat him at a keyboard and manipulated the cat such that it played a song Mr. Schmidt wrote. Mr. Schmidt had recently posted the old video on YouTube. Keyboard Cat was blowing up.

Mr. Lashes started helping his family friend, creating a social-media strategy to fan the cat's grass-roots popularity. He told Mr. Schmidt to adopt a new cat and make more videos. Then came the licensing deals with T-shirt, toy and novelty gift companies. Soon, Mr. Lashes was making deals for the cat to appear in marketing and ad campaigns. In all, Mr. Schmidt says he has made nearly $300,000 from Keyboard Cat deals Mr. Lashes has arranged.

Mr. Lashes now lives in West Hollywood, Calif., where he works out of his one-bedroom condo. His newest client is Princess Monster Truck, a cat with an underbite. "When it comes to cats, Ben knows who is going to be big," says Christopher Torres, a client of Mr. Lashes and the creator of Nyan Cat, a digital, square-shaped feline. Mr. Lashes also represents other photographs, images, sayings or ideas that spread online and become cultural inside jokes.

Mr. Lashes says he tries to help his clients protect their brands as well.

Last month, Messrs. Torres and Schmidt filed a lawsuit with the U.S. District Court in the central district of California. They allege that 5th Cell and Warner Bros.—respectively the developer and publisher of the Scribblenauts franchise of videogames—have infringed on the copyright and trademark right of Keyboard Cat and Nyan Cat, by including the characters in Scribblenauts games.

"If you're a big corporation and you normally pay for the use of these things, we will come after you," says Kia Kamran, an attorney who works with Mr. Lashes on his clients' transaction matters and who also represents the intellectual property rights of the tattoo on former boxer Mike Tyson's face.

Mr. Lashes says he is driven by a desire to "protect the little guy" but also to have fun. At the South by Southwest tech convention in Austin, Texas, in March, he arranged a paid-appearance deal for Grumpy Cat from the website Mashable. For two-hour stretches over three days, the cat lay on a cushioned pedestal in Mashable's tent and conventioneers waited in line for hours to have their photo taken with the nonplused puss.

The logistics weren't that complicated to work through—Grumpy Cat was already scheduled to be in Austin to tape a celebrity edition of an online game show, "Will Kitty Play With It?"

As part of the travel expenses covered by Friskies, the cat-food brand that sponsors the game show, Mr. Bundesen says he chauffeured Grumpy Cat around Austin in a black BMW X5, with tinted windows. When they left the final day of the Mashable appearance, he says the car was swamped by 40 to 50 people taking photos of the cat through the car windows. "It was like the paparazzi," he says.